“He was our little superhero and put the biggest fight up but he was needed else where. There are no words to describe how heart broken we are.”

Image copyrightOwen HumphreysImage caption Bradley’s mum Gemma Lowery had previously said his deterioration had been “heartbreaking”

In a statement Sunderland FC extended its “‘love and support” to Bradley’s family.

It said: “He had a special relationship with Jermain Defoe and their feelings for each other were evident for all to see. Jermain, naturally, is heartbroken.”

Bradley underwent treatment and was in remission, but relapsed last year.

Well-wishers raised more than 700,000 in 2016 to pay for him to be given antibody treatment in New York, but medics then found his cancer had grown and his family was informed his illness was terminal.

Image copyrightGetty ImagesImage caption Bradley was a mascot for England when they played Lithuania in March

In December, Bradley’s parents Gemma and Carl, from Blackhall Colliery, County Durham, were told he only had “months to live”.

Four months later they were told the latest and final round of his treatment had failed.

He underwent “tumour-shrinking treatment” at Newcastle’s Royal Victoria Infirmary but the cancer continued to spread.

On 24 May, Mrs Lowery said Bradley had left hospital to start palliative care at home, adding more tumours had been found and further radiotherapy was planned.

Then, on 28 June the family wrote on Facebook: “Bradley is deteriorating fast, his temperature is going very high his breathing very fast his oxygen levels low.

Image copyrightPAImage caption Bradley walked down the red carpet at the BBC’s Sports Personality of the Year in 2016

“He is sleeping most the time apart from odd times awake. We knew this was coming but we are heartbroken beyond words.”

He was also given honorary 41st place in the race card for the Grand National at Aintree in April.

On 30 June a charity single, “Smile For Bradley” by LIV’n’G, entered the singles chart at number 28. All proceeds from the song will go to the Bradley Lowery Foundation, which has been set up in his honour.